/*
 * dsf2flac - http://code.google.com/p/dsf2flac/
 *
 * A file conversion tool for translating dsf dsd audio files into
 * flac pcm audio files.
 *
 * Copyright (c) 2013 by respective authors.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *
 * Acknowledgments
 *
 * Many thanks to the following authors and projects whose work has greatly
 * helped the development of this tool.
 *
 *
 * Sebastian Gesemann - dsd2pcm (http://code.google.com/p/dsd2pcm/)
 * SACD Ripper (http://code.google.com/p/sacd-ripper/)
 * Maxim V.Anisiutkin - foo_input_sacd (http://sourceforge.net/projects/sacddecoder/files/)
 * Vladislav Goncharov - foo_input_sacd_hq (http://vladgsound.wordpress.com)
 * Jesus R - www.sonore.us
 *
 */

#include "dop_packer.h"

dsf2flac_int32 odd_marker = 0x00050000;
dsf2flac_int32 even_marker  = 0xFFFA0000;

DopPacker::DopPacker(DsdSampleReader *r) {
	reader = r;
	// buffer length needs to be at least 2 chars long
	if (2 > reader->getBufferLength())
		reader->setBufferLength(2);
}

DopPacker::~DopPacker() {

}

//unsigned char reverse(unsigned char b) {
//   b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
//   b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
//   b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
//   return b;
//}

unsigned char reverse(unsigned char x)
{
    static const unsigned char table[] = {
        0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
        0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
        0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
        0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
        0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
        0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
        0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
        0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
        0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
        0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
        0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
        0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
        0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
        0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
        0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
        0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
        0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
        0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
        0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
        0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
        0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
        0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
        0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
        0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
        0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
        0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
        0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
        0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
        0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
        0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
        0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
        0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
    };
    return table[x];
}

void DopPacker::pack_buffer(dsf2flac_int32 *buffer, dsf2flac_uint32 bufferLen) {
	// check the buffer seems sensible
	div_t d = div(bufferLen,reader->getNumChannels());
	if (d.rem) {
		fputs("Buffer length is not a multiple of getNumChannels()",stderr);
		exit(EXIT_FAILURE);
	}
	// get the sample buffer
	boost::circular_buffer<dsf2flac_uint8>* buff = reader->getBuffer();
	for (int i=0; i<d.quot ; i++) {

		dsf2flac_int32 packed_sample;
		dsf2flac_uint8 byte1;
		dsf2flac_uint8 byte2;

		// step the buffer right away so that the first sample sits in position 1 in the buffer (second in position 0)
		reader->step();

		for (dsf2flac_uint32 c=0; c<reader->getNumChannels(); c++) {

			if (( (reader->getPosition() - 8) % 32) != 0)
				packed_sample = even_marker;
			else
				packed_sample = odd_marker;

			byte1 = buff[c][1];
			byte2 = buff[c][0];

			if (reader->msbIsPlayedFirst()) {
				byte1 = reverse(byte1);
				byte2 = reverse(byte2);
			}

			packed_sample += ((dsf2flac_int32) byte1) << 8;
			packed_sample += ((dsf2flac_int32) byte2);

			buffer[i*reader->getNumChannels()+c] = packed_sample;
		}

		reader->step();
	}
}

